A review and preview of proton microprobes

A review of the development of low energy microprobes during the last 15 years and their applications in trace element analysis utilizing the PIXE technique is provided. The expansion of this technology and the evolution of the micro-PIXE technique for higher energy machines is also discussed and new avenues for research outlined. The University of Manitoba Spiral Ridge Cyclotron, which produces proton beams from 20 to 50 MeV, is the site of a micro-PIXE facility, which is currently under construction. This microprobe consists of two stages. The series of collimators that make up the first stage is followed by a "Russian Quadruplet" of magnetic quadrupoles, which were constructed at the Magnet Facility at the University of Manitoba. These will give a beam spot on target of ∼10 μm at 35 MeV. A new concept which will provide for future diversity with little modification is being incorporated in the target holder. Finally, past applications of PIXE at this facility and their expansion into micro-PIXE, in addition to future modifications of the system, are discussed.